Nanoparticles, and particularly gold nanoparticles, have unique physical and chemical properties. These properties have increased interest in improving nanoparticles synthesis and creating commercially-feasible processes. Conventionally, nanoparticles are deposited using physical vapor deposition (PVD) methods, such as co-evaporation and co-sputtering.
These processes are complex and result in low yield of nanoparticles with the desired composition, size, and size distribution. Further, operation of PVD processes is expensive and generates relatively low throughput. In particular, PVD processes operate in vacuum environments. Loading substrates into chambers and evacuating air from the chamber to lower the pressure into the operational range for the PVD process requires time, which reduces throughput. Further, the deposition process is relatively uncontrolled and may result in wasted materials. For example, in a co-sputtering process, the materials are deposited across an area much wider than just the substrate. Thus, if the materials are expensive, such as when gold nanoparticles are deposited, the wasted material may represent a large expense.
One conventional solution for improving nanoparticles deposition processes is printing the nanoparticles with an inkjet printer or other printer. An advantage of inkjet printing is the lack of requirement for a vacuum environment. The conventional process involves preparing a stable ink solution of nanoparticles in a solvent through wet chemical synthesis. The stable solution is then printed on a substrate with the inkjet printer. However, this process has several disadvantages. For example, the preparation of the stable ink solution is difficult and requires significant preparation time and purification before printing the ink with the inkjet printer. Moreover, infiltration of a porous medium is limited to the size of the nanoparticles used.